Simple 1D Model Research Articles

Nano-composite system of traditional Chinese medicine for ocular applications: molecular docking and three-dimensional modeling insight for intelligent drug evaluation.

The absorption of drugs was impeded in the posterior part of the eye due to the special structure. In addition, it was crucial to comprehend transport laws of molecules in ocular drug delivery for designing effective strategies. However, the current quality evaluation methods of the eye were backward and lack of dynamic monitoring of drug processes in vivo. Herein, nano-drug delivery system and three-dimensional (3D) model were combined to overcome the problems of low bioavailability and diffusion law. The model drugs were screened by molecular docking. The flexible nano-liposome (FNL) and temperature-sensitive gel (TSG) composite formulation was characterized through comprehensive evaluation. COMSOL software was utilized to build 3D eyeball to predict the bioavailability of drugs. The size of the preparation was about 98.34 nm which is relatively optimal for the enhanced permeability of the eyes. The formulation showed a stronger safety and non-irritant. The pharmacokinetics results of aqueous humor showed that the AUC of two drugs in this system increased by 3.79 and 3.94 times, respectively. The results of 3D calculation model proved that the concentrations of drugs reaching the retina were 1.90×10-5 mol/m3 and 6.37×10-6 mol/m3. In conclusion, the FNL-TSG markedly improved the bioavailability of multiple components in the eye. More importantly, a simplified 3D model was developed to preliminarily forecast the bioavailability of the retina after drug infusion, providing technical support for the accurate evaluation of ocular drug delivery. It provided new pattern for the development of intelligent versatile ophthalmic preparations.

Neutronic Assessments towards a Novel First Wall Design for a Stellarator Fusion Reactor with Dual Coolant Lithium Lead Breeding Blanket

The Stellarator Power Plant Studies Prospective R&D Work Package in the Eurofusion Programme was settled to bring the stellarator engineering to maturity, so that stellarators and particularly the HELIAS (HELical-axis Advanced Stellarator) configuration could be a possible alternative to tokamaks. However, its complex geometry makes designing a Breeding Blanket (BB) that fully satisfies the requirements for such a HELIAS configuration, which is a difficult task. Taking advantage of the acquired experience in BB design for DEMO tokamak, CIEMAT is leading the development of a Dual Coolant Lithium Lead (DCLL) BB for a HELIAS configuration. To answer the specific HELIAS challenges, new and advanced solutions have been proposed, such as the use of fully detached First Wall (FW) based on liquid metal Capillary Porous Systems (CPS). The proposed solutions have been studied in a simplified 1D model that can help to estimate the relative variations in Tritium Breeding Ratio (TBR) and displacement per atom (dpa) to verify their effectiveness in simplifying the BB integration and improving the machine availability while keeping the main BB nuclear functions (i.e., tritium breeding, heat extraction and shielding). This preliminary study demonstrates that the use of FW CPS would drastically reduce the radiation damage received by the blanket by 29% in some of the selected configurations along with a small decrease of 4.9% in TBR. This could even be improved to just a 3.8% TBR reduction by using a graphite reflector. Such an impact on the TBR is considered affordable, and the results presented, although preliminary in essence, have shown the existence of margins for further development of the FW CPS concept for HELIAS, as they have been not found, at least to date, to be significant showstoppers for the use of this technological solution.

Nature and origin of an undetected seismic phase in waveforms from Southern Tyrrhenian (Italy) intermediate-depth and deep earthquakes: first evidence for the phase-A in the subducted uppermost lithospheric mantle?

We have found a previously unreported later seismic phase in seismograms of European seismic stations from intermediate-depth and deep earthquakes of the Southern Tyrrhenian subduction zone. We observe this phase at stations from 6 to 9° from the epicentre, towards north. Only seismograms of earthquakes located in a well-defined region of the slab, in the depth range of 215–320 km, show the later x-phase. In this work, we describe the nature and possible origin of this phase, and we provide a simple 2D model to explain the observed arrival times. Our analyses reveal that the x-phase propagates downward in a high velocity layer, possibly located within the deepest part of the slab. We suggest that this layer reveals the presence of the dense hydrous magnesium silicate phase A, introduced from petrological laboratory experiments, inferred to carry water in the upper mantle and predicted to be found in cold subduction zones.

Cartilage thickness mismatches in patellar osteochondral allograft transplants affect local cartilage stresses.

Osteochondral allograft implantation is a form of cartilage transplant in which a cylindrical graft of cartilage and subchondral bone from a donor is implanted into a patient's prepared articular defect site. No standard exists for matching the cartilage thickness of the donor and recipient. The goal of this study was to use finite element (FE)analysis to identify the effect of cartilage thickness mismatches between donor and recipient cartilage on cartilage stresses in patellar transplants. Two types of FE models were used: patient-specific 3D models and simplified 2D models. 3D models highlighted which geometric features produced high-stress regions in the patellar cartilage and provided ranges for the parameter sweeps that were conducted with 2D models. 2D models revealed that larger thickness mismatches, thicker recipient cartilage, and a donor-to-recipient cartilage thickness ratio (DRCR) < 1 led to higher stresses at the interface between the donor and recipient cartilage. A surface angle between the donor-recipient cartilage interface and cartilage surface normal near the graft boundary increased stresses when DRCR > 1, with the largest increaseobserved for an angle of 15°. A surface angle decreased stresses when DRCR < 1. Clinical Significance: This study highlights a potential mechanism to explain the high rates of failure of patellar OCAs. Additionally, the relationship between geometric features and stresses explored in this study led to a hypothetical scoring system that indicates which transplanted patellar grafts may have a higher risk of failure.

Computer-aided determination of the effective diffusion coefficient of a gas diffusion layer for polymer electrolyte fuel cells

Accurate measurement of the gas diffusivity in a gas diffusion layer (GDL) for polymer electrolyte fuel cells (PEFCs) is extremely important in order to improve the performance of PEFCs and design fuel cell stacks. In the present study, in order to improve the accuracy in the determination of the gas diffusivity when uisng the simple and inexpensive method newly proposed by Yoshimune (2022), which uses an infrared absorption carbon dioxide sensor, three-dimensional (3D) simulations reproducing the experiments are performed. The results reveal that the gas transport resistance of the measurement apparatus is not small (approximately seven times higher than that of a commercial carbon paper (TGP-H060, Toray)), and the 3D simulation, which considers the resistance, reduces the error in the effective diffusion coefficient of the GDL by 25%. The effective diffusion coefficient for a new sample can be determined using the simulation results already obtained, when the apparatus is unchanged. In addition, a new one-dimensional (1D) model extended from the simple 1D model presented in Yoshimune (2022) is proposed. Since the extended model incorporates the gas transport resistance of the apparatus and dispenses with the generation of computational grids and the use of an expensive computer needed in conducting 3D simulations, this model enables us to obtain the accurate effective diffusion coefficient of a GDL with ease even when using a measurement apparatus with different sizes.

Mechanical Modeling of Pre‐Eruptive Magma Propagation Scenarios at Calderas

AbstractSimulating magma propagation pathways requires both a well‐calibrated model for the stress state of the volcano and models for dike advance within such a stress field. Here, we establish a framework for calculating computationally efficient and flexible magma propagation scenarios in the presence of caldera structures. We first develop a three‐dimensional (3D) numerical model for the stress state at volcanoes with mild topography, including the stress induced by surface loads and unloading due to the formation of caldera depressions. Then, we introduce a new, simplified 3D model of dike propagation. Such a model captures the complexity of 3D magma trajectories with low running time, and can backtrack dikes from a vent to the magma storage region. We compare the new dike propagation model to a previously published 3D model. Finally, we employ the simplified model to produce shallow dike propagation scenarios for a set of synthetic caldera settings with increasingly complex topographies. The resulting synthetic magma pathways and eruptive vent locations broadly reproduce the variability observed in natural calderas.

An Optimized Workflow to Generate and Characterize iPSC-Derived Motor Neuron (MN) Spheroids.

A multitude of in vitro models based on induced pluripotent stem cell (iPSC)-derived motor neurons (MNs) have been developed to investigate the underlying causes of selective MN degeneration in motor neuron diseases (MNDs). For instance, spheroids are simple 3D models that have the potential to be generated in large numbers that can be used across different assays. In this study, we generated MN spheroids and developed a workflow to analyze them. To start, the morphological profiling of the spheroids was achieved by developing a pipeline to obtain measurements of their size and shape. Next, we confirmed the expression of different MN markers at the transcript and protein levels by qPCR and immunocytochemistry of tissue-cleared samples, respectively. Finally, we assessed the capacity of the MN spheroids to display functional activity in the form of action potentials and bursts using a microelectrode array approach. Although most of the cells displayed an MN identity, we also characterized the presence of other cell types, namely interneurons and oligodendrocytes, which share the same neural progenitor pool with MNs. In summary, we successfully developed an MN 3D model, and we optimized a workflow that can be applied to perform its morphological, gene expression, protein, and functional profiling over time.

Numerical optimization of highly loaded microtextured contacts: understanding and mastering complexity

PurposeMicrotextured surfaces can reduce friction in tribological systems under certain contact conditions. Because it is very time-consuming to determine suitable texture patterns experimentally, numerical approaches to the design of microtextures are increasingly gaining acceptance. The purpose of this paper is to investigate to what extent the selected modeling approach affects optimized texturing.Design/methodology/approachUsing the cam/tappet contact as an application-oriented example, a simplified 2D and a full 3D model are developed for determining the best possible texturing via a design study. The study explores elongated Gaussian-shaped texture elements for this purpose. The optima of the simplified 2D simulation model and the full 3D model are compared with each other to draw conclusions about the influence of the modeling strategy. The target value here is the solid body friction in contact.FindingsFor the elongated texture elements used, both the simplified 2D model and the full model result in very similar optimal texture patterns. In the selected application, the simplified simulation model can significantly reduce the computational effort without affecting the optimization result.Originality/valueDepending on the selected use case, the simulation effort required for microtexture optimization can be significantly reduced by comparing different models first. Therefore, an exact physical replica of the real contact is not necessarily the primary goal when it comes to texture selection based on numerical simulations.

The effect of icing severity on wind turbine ice protection systems efficiency

In the past years, there has been a gain of interest in wind turbine Ice Protection Systems (IPS) as wind farm owners realize the extent of their ice-induced losses. More and more wind turbine manufacturers are now offering IPSs in their cold climate packages. IPS retrofits are now available to minimize icing losses on existing unheated wind turbines. With this growth in interest, questions about the efficiency of those systems arise. Field experience has shown that these systems can be ineffective in certain ambient conditions which led to the concept of IPS performance envelopes. These envelopes lay out on a wind speed vs ambient temperature map the conditions where IPSs are expected to be effective. While these envelopes can give a good overlook of the IPSs efficiency in post-icing conditions, they neglect the effect that icing severity can have on IPS effectiveness. This paper presents a simple 1D model for hot-air IPS able to generate performance envelopes considering the icing severity. This model was validated with the production data of six different icing events. It has been shown to be coherent with the observed efficiency of the hot air IPS.

Implementation of SOLPS-ITER code with new Grad–Zhdanov module for D–T mixture

A new Grad–Zhdanov module is implemented into the SOLPS-ITER code for calculation of the parallel kinetic coefficients. A complete, multi-ion generalization is performed, relaxing the heavy impurity assumption. A JET-like D+T+Ne test simulation is conducted to demonstrate the ability to model a 50/50 deuterium (D) and tritium (T) mixture in SOLPS-ITER. More than 30% T build-up with respect to D is observed in different parts of the simulation domain, in particular at the high field side. A T predominance over D is also observed near both the inner and outer targets. It is a result of the different effective diffusion, dominated by charge-exchange processes, for the D and T neutral species. A simple 1D model is proposed to describe this phenomenon. The contribution to the differing D and T distribution in different regions from the Grad–Zhdanov thermal force is also studied. Due to the thermal force and the D/T poloidal flow from the low field side to the high field side, the prevalence of the T species over D is found at the high field side at the X-point level. The latter leads to an inner–outer divertor asymmetry of . However, the effect is relatively small due to the close D and T masses. It is further shown that the infinite ion mass difference limit, which is used for the derivation of the Zhdanov-Yushmanov analytical expressions and applied for the thermal force coefficient calculation previously used in the SOLPS-ITER code, overestimates significantly. Thus, the old SOLPS-ITER model should not be applied for D–T simulations. Finally, possible experimental studies of the D and T spatial separation due to the new effects revealed by this modelling are discussed.

Social Search and Resource Clustering as Emergent Stable States.

Social search has stably evolved across various species and is often used by humans to search for resources (such as food, information, social partners). In turn, these resources frequently come distributed in patches or clusters. In the current work, we use an ecologically inspired agent-based model to investigate whether social search and clustering are stable outcomes of the dynamical mutual interactions between the two. While previous research has studied unidirectional influences of social search on resource clustering and vice versa, the current work investigates the consequential patterns emerging from their two-way interactions over time. In our model, consumers evolved search strategies (ranging from competitive to social) as adaptations to their environmental resource structures, and resources varied in distributions (ranging from random to clustered) that were shaped by agents' consumption patterns. Across four experiments, we systematically analyzed the patterns of influence that search strategies and environment structure have on each other to identify stable attractor states of both. In Experiment 1, we fixed resource clustering at various levels and observed its influence on social search, and in Experiment 2, we observed the influence of social search on resource distribution. In both these experiments we found that increasing levels of one variable produced increases in the other; however, at very high levels of the manipulated variable, the dependent variable tended to fall. Finally in Experiments 3 and 4, we studied the dynamics that arose when resource clustering and social search could both change and mutually influence each other, finding that low levels of social search and clustering were stable attractor states. Our simple 2D model yielded results that qualitatively resemble those across a wide range of search domains (from physical search for food to abstract search for information), highlighting some stable outcomes of mutually interacting consumer/resource systems.

A microphysiological system for studying human bone biology under simultaneous control of oxygen tension and mechanical loading.

Throughout life, continuous remodelling is part of human bone biology and depends on the simultaneous action of physicochemical parameters such as oxygen tension and varying mechanical load. Thus, suitable model systems are needed, which allow concomitant modulation of these factors to recapitulate in vivo bone formation. Here, we report on the development of a first microphysiological system (MPS) that enables perfusion, environment-independent regulation of the oxygen tension as well as precise quantification and control of mechanical load. To demonstrate the use of the MPS for future studies on the (patho-)biology of bone, we built a simplified 3D model for early de novo bone formation. Primary human osteoblasts (OBs), which are the key players during this process, were seeded onto type I collagen scaffolds and cultured in the MPS. We could not only monitor cell viability and metabolism of OBs under varied physicochemical conditions, but also visualise the mineralisation of the extracellular matrix. In summary, we present a MPS that uniquely combines the independent control of physicochemical parameters and allows investigation of their influence on bone biology. We consider our MPS highly valuable to gain deeper insights into (patho-)physiological processes of bone formation in the future.

An Intelligent Virtual Environment for Designers with Reduced Motor Abilities

Conventional CAD modelling software demands substantial utilisation of input modalities like the keyboard and mouse for creating 3-dimensional (3D) models. The dexterity measures involved in controlling input modalities could pose challenges to users with motor disabilities—including the inability to move their limbs, particularly their upper and lower arms, and fingers, due to traumatic damage or congenital problems. In order to meet these challenges, this paper proposes a virtual reality (VR)-based medium to help users with motor disabilities build simple 3D models for architectural design. The concept of operating buttons using head-gaze in the VR environment has been utilised to perform scaling—a 3D object manipulation method—to create simplified building models. Moreover, navigation in the VR space using tilting of the head has been employed with the user seated on a revolving chair, thus eliminating the need for any limbic movement. Unity game engine was used to develop two variations of the VR model with a different button layout for creating simple cuboidal volumes mimicking buildings in the virtual environment. Both variations have been tested with 32 individuals against a specific performance indicator (i.e., task completion time) and self-reported metrics, such as the perception of effort applied and degree of visual clutter, followed by retrospective participant feedback sessions. One of the VR application's variants (i.e., variant 1) produced promising results regarding overall usability and effort demand. This paper also proposes a methodological framework for an AI-based, intelligent, and adaptive VR application interface that caters to the user's abilities and pain points in real-time. In the future, this framework could be instrumental in creating a comprehensive gaze-based VR tool for 3D modelling having multiple functions to help users with motor disabilities.

Незвіданий облік породільних барлогів ведмедя білого (Ursus maritimus) на островах Врангеля та Геральда у 1982 році

In March–May 1982, a local expedition worked in the Arctic, in the east of Wrangel Island (WI) and Herald Island (HI), to carry out a survey of polar bear dens. The results of that expedition have not been published. The author has found a copy manuscript of the expedition diary and has highlighted the key results. For two months, five ex-plorers had been surveying the area and found 139 dens and sighted 57 bears (♀ad + juv). The average number of offspring (ANO) was 1.43 on WI and 1.86 on HI. The number of successful offspring on WI usually was one or two cubs, or even three on HI. Based on the available sample (n=44) it was shown that when taking into account the survey data of cub traces in calculations of ANO (on WI), the obtained results do not differ notable. The time that lasted from the date of the opening of the den to the date of the final leave of the den by females (with or without the young) was 4 to 14 days, but most often 6 days. The highest frequency of den opening was noted on 27–28 March. Four cases of death of cubs, including a newborn, were recorded. The fate of 43 dens was monitored and measurements of 11 dens were taken. Two unusual dens were found: one with a very complex corridor and another one with a 4.5 m long vertical tunnel. Simplified 3D models of dens were given in the article for the first time proving that linear measurements practiced by researchers give a primitive picture of the den structure. After leaving the maternity den, the female can build temporary, simple shelter for herself and the young. During 1964–2020, dens were found on these islands only on the ground, and in 1980 the author found several dens on the sea, among ridges of pressured ice. The article is amended by the author’s estimations regarding the place of the polar bear in ecologi-cal pyramid of those islands. Recommendations are given for the improvement of polar bear survey techniques. The publication of a Ukrainian language article on the biology of U. maritimus is rare for the school of Ukrainian mammalogists and is of clear enlightening importance for scientists, lecturers, students, Wikipedia editors, and oth-ers, as well as a contribution of the author to the Ukrainian body of literature on the animal world of the Arctic.

Identification of Wind-Induced Particle Resuspension in Urban Environment Using CFD Modelling

Air pollution caused by particulate matter (PM) is a current problem in many cities. With the introduction of strict emission limits and electric cars, lower particle production is expected in the future. However, there are sources of particles that cannot be easily influenced. These include resuspension, where particles deposited on surfaces re-enter the air, causing pollution multiple times. Resuspension can account for up to 18% of the total emissions in some cases. The present paper focuses on the use of the computational fluid dynamics (CFD) tools to describe the flow in a street canyon where resuspension by wind occurs. Based on the calculated flow, a resuspension model is applied to see where resuspension occurs and how far the particles can travel. The shear stresses on the surfaces and the character of the flow field in the boundary layer are evaluated. Different building configurations and flow parameters are tested using a simple 2D model. The model makes it possible to see in which parts of the street canyon resuspension can occur. It shows that the particles leave the street canyon only from the surfaces where the conditions are suitable for resuspension. These particles then enter the mainstream. However, most of the particles stay in the canyon, which can cause resuspension to pollute the air repeatedly. This effect can have a severe impact on human health. The total dispersion of particles in the urban environment is evaluated. The results may be useful for cities that clean the streets, as it is clear which areas will benefit most from the cleaning.

Dust processing in protoplanetary envelopes as the origin of hot minerals in comets

ABSTRACT Crystalline silicates are found in a large number of comets. These pose a long-standing conundrum for Solar system formation models as they can only be created in the inner hot disc at temperatures higher than 800 K, and there is no obvious mechanism to transport them out into the comets formation region. Here, we propose that these particles could have formed inside the hydrostatic envelopes surrounding young protoplanets still embedded in the protoplanetary disc. Using a simplified 1D model we investigate the thermal structure of these envelopes, and find that for core masses ranging from 0.08 to 1.5 M⊕, located anywhere between 1 and 30 au, the temperature and pressure at the base of the envelopes are high enough to quickly vapourize silicate particles of various sizes. Moreover, if the grain abundance is atleast solar, these envelopes become fully convective, allowing for dust ejection across the Bondi radius back into the disc. Amorphous silicates are hence thermally processed into crystalline particles in these envelopes, and then transported back to disc through convective diffusion to be finally incorporated into the cometary building blocks.

Non-axisymmetric analysis of the vertical dynamic response of large-diameter pile in layered soil

In the low-strain integrity test, the excitation hammer usually impacts the center of the pile top. However, in practice, the excitation hammer is often not applied precisely at the center of the pile top. The hammer-pile-soil system, especially for the large-diameter pile, is no longer axisymmetric. The existing axisymmetric models are no longer suitable for describing the propagation of these stress waves in piles under vertical non-axisymmetric excitation load. This paper introduces a simplified three-dimensional (3D) model to investigate the non-axisymmetric dynamic characteristics of the large-diameter pile under non-axisymmetric excitation load in layered soil. The suitability and accuracy of the simplified 3D model are verified by comparison with the numerical solutions and other existing results. Meanwhile, the applicable pile radius range of the simplified 3D model is obtained by comparing it with the numerical solution. Finally, the influence of the excitation load and the pile properties on the non-axisymmetric dynamic characteristics of the large-diameter pile is discussed. Some valuable suggestions for weaking the high-frequency interference of normal large-diameter piles are provided for practical engineering.

Control-oriented computational fuel cell dynamics modeling – Model order reduction vs. computational speed

Many 1D computational fuel cell dynamics models are established to predict the performance of proton exchange membrane (PEM) fuel cells for control purposes. The 1D models are of high fidelity over a wide range of operating conditions in comparison with empirical and analytical models and less dependent on a large quantity of experimental data in comparison with data-driven models. However, the relation between the various simplified 1D models and their computing efficiency has not been fully understood. Therefore, the present study investigates the trade-off relation between the model order reduction and computational speed of control-oriented 1D models. A full-order model, considering all essential physical phenomena, is validated against experimental data. Seven reduced-order models, depending on whether convection, liquid water, and thermal effects are simulated, are compared with the full-order model in terms of accuracy and computational speed under the same boundary and initial conditions. The results indicate that the two-phase flow has a more significant impact on the cell performance than non-isothermal and convection effects at high relative humidity and current density conditions. The computing speed of the reduced-order model, in which the convection, liquid water, and temperature variation are omitted, can be 140 times faster than the full-order model.

Detailed CFD transient heat transfer modelling in a brake friction system

In a brake system the contact between the friction grooves of the discs and the steel elements leads to a consistent heat dissipation that is excised by the oil thermal vector in its flowing along the grooves channels. These are very complicated physical system were many variables may be taken in consideration, first of all the extensive integration of the different time scheduling actions that take place and that characterizes the translation of the interacting bodies and the correspondent deceleration, and also the heat dissipation derived from this contact. The simulations of similar physical system may result in too expensive computational efforts leading to very complicated simulations that need to take in account an extensive coupling between many physics, first of all the solid/liquid heat transfer and then the turbulence and the bi-phase models for the oil/air mixture that serves as thermal refrigerator vector in the braking system. Herein a simplified 3D model that focuses only on a discs / piston coupling is presented were the braking action is simulated in a simplified way modelling the velocity of rotation of the elements and the dissipated heat during the braking cycle. Focusing on the grooves channels the oil flows and thermal averaged flows are presented and detail contours are used to characterise a single brake event.

Analytical modeling of Ni–Co based multilayer bimorph actuators involving dual insulation layers

This paper proposes a new design of multilayered bimorph electrothermal actuators based on a Ni and Co alloy (Ni–Co) substrate and analytical models to estimate their performance. The proposed bimorph actuator consists of a flexible Ni–Co substrate having high coefficient of thermal expansion (CTE) along with two insulation (low-CTE materials) and Pt heater layers. A multilayered thermo-mechanical model to estimate the tip deflection was derived based on Timoshenko’s classical model for metal bilayers. An analytical model based on the Euler–Bernoulli beam theory was also derived to calculate the blocking force of the multilayered actuators. An appropriate layer composition of the low-CTE layers was derived based on the analytical models and lattice parameters of the adjacent layers: the performance of the bimorph actuator was significantly improved when the low-CTE layers are composed of a dual layer instead of a single layer of SiO2. The analytical solutions of the simplified 3D models were then compared with finite element analysis (FEA) and experimental results. In the comparison of the tip deflection, the analytical solution of the three-layer actuator omitting the Pt heater was similar to the FEA result and the experimental result compensating for the initial dead zone. In the comparison of the blocking force, the analytical solution was also similar to the FEA results, though there was a deviation from the experimental results. Abnormal behavior of the actuator was observed in the experimental result of the blocking force, and the cause was investigated in this study.